This invention relates to a recessed center vane of a straight-through solid cone spray nozzle. Straight-through spray nozzles with a solid cone spray are old and well known in the art as shown, for example, in co-pending U.S. patent application Ser. No. 322,169 filed Nov. 17, 1981 and issued on Sept. 27, 1983 as U.S. Pat. No. 4,406,407 entitled "High Flow Low Energy Solid Jet Nozzle" and assigned to the assignee of the present invention. Straight-through solid cone nozzles are also commercially available as, for example, by Wm. Steinen Mfg. Co. of Parsippany, N.J., the assignee of the present application.
Solid cone nozzles commonly comprise a straight-through nozzle body having an input chamber which is connected to a fluid-connecting conduit of given diameter and flow capacity for fluids at a given pressure. A center vane is placed in the input chamber of the nozzle body and communicates between the input section and an axial discharge orifice of the nozzle body. The center vane commonly is provided with a plurality of slots which differ in number, angular configuration and size depending upon the desired end use. It is desirable to design the unit so that the fluid flow per unit of time at any unit area across the cone is as uniform as possible relative to other unit area in the same plane across the cone and thus maintain a solid spray cone.
In the past, the vane for the spray nozzle was custom-made for a particular application to obtain a solid spray cone under given conditions of input pipe size, input pressure and volumetric fluid flow. It was not possible to simply change the scale of a given vane design when going from one input pipe size to another or from one input pressure to another because the resulting spray pattern would no longer be uniform and generally would become hollow or otherwise unsuitable. Thus a new vane design was required for each set of new pressure, volumetric flow and pipe diameter parameters. These vane designs are time-consuming since they are generally reached only after considerable trial and error methods and the cost of the resulting nozzle is substantially increased.
Parameters of the vane design which can be changed include the vane thickness, changes in the number of slots or channel openings and their location, changes in the angular relationship of the slot to the axis of the vane, changes in the cross-sectional geometry of the slot or channel openings through the vane and changes in the depth of the vane recess. For example, in the past, when the flow rate was increased, the vane design would be commonly modified by increasing the number of slots through the vane and/or by increasing slot width. Care had to be taken, however, since, if the slots became too wide or too numerous, fluid distribution over the area of the spray cone was poor. Similarly, if the number of slots became too great, the individual slot cross-sectional area was smaller and the slots were easily clogged by particulates carried in the fluid. Care also had to be taken during the design not to have the slots so large that the webs between the slots within the vane were structurally weakened to the point where they could easily fail during manufacture or in operation. Care also had to be taken to ensure against forming a hollow spray cone pattern.
This invention relates to full cone spray nozzles having substantially even distribution of the liquid throughout the entire cross-sectional spray pattern, as contrasted with hollow cone sprays where no liquid is present in the center portion of the spray.
As previously noted, full cone spray nozzles are well known in the art, and are comprised of a nozzle body with an internal chamber having an input end into which liquid can be introduced and a reduced diameter axial discharge orifice at the other end of the chamber. Within the chamber and spaced from the discharge orifice, a center vane means is provided so that liquid passing through the chamber has a swirling or rotative motion applied thereto coupled with a controlled amount of turbulence. When the liquid is discharged from the orifice, the liquid assumes a conical form and should have uniform distribution of the particles of fluid throughout the transverse cross-sectional area of the spray.
In full cone spray nozzles, the capacity is determined by the cross-sectional area of discharge orifice and the operating pressure. In order to achieve uniformity of particle distribution in the spray, the dimensional relationships between the orifice of the center vane and the internal chamber constitute variables that contribute and interact in attaining the desired results. Full cone spray nozzles have a wide field of usefulness and there are large numbers of nozzles that are commercially available to provide nozzles having the desired combination of capacity, spray angle and pressure to satisfy the majority of design situations. There may be at least 40 different nozzle sizes at 40 pounds per square inch liquid pressure to provide capacities of from one (1) gallon per minute to 15,000 gallons per minute with spray angles ranging between 20.degree. and 140.degree..
In accordance with the invention, a novel center vane geometry has been produced which has been found to form a uniform solid cone spray for a wide range of pipe diameters, volumetric flow and input fluid pressures.
The vane geometry of the invention applies to pipes of any diameter from one-eighth (0.125) inch to 24 inches employing input pressures of from 1 p.s.i. to 150 p.s.i. and requiring a flow of between 1 to 15,000 gallons per minute.
The novel design of the invention was reached through extensive experimentation and trial and error which revealed the following relationships which must be maintained in the vane design to retain a solid spray cone:
(1) The number of channel slots employed for the center vane is three (3). Each slot is spaced 120.degree. from the other and has a generally rectangular cross-section including a flat bottom.
(2) The slots are placed at an angle to the axis of the vane. For a precise design, the angle could be one-half the desired exit or spray angle, where the slot angle is measured between the center line axis of the vane and a line extending along the center of the bottom of each slot. However, we have found that the 45.degree. angle, for the most popular spray angle of 90.degree., could be retained and an adjustment in the exit flare of the nozzle could be made to adjust for larger or smaller spray angles.
(3) Each slot has a width equal to one-fourth (0.25) of the nozzle diameter and a depth equal to nozzle diameter divided by the number of slots, i.e. three (3).
(4) The vane length, measured along the vane axis, is equal to one-half (0.5) the nozzle diameter and the vane diameter is equal to the pipe or nozzle diameter.
(5) The vane is spaced from the orifice by a distance equal to the diameter of the vane or diameter of the nozzle.
(6) The total inlet opening area of the vane is substantially less than the outlet opening area of the vane. This is accomplished by having a recess cut into the outlet end of the vane. This recess permits the creation of a solid cone spray and by properly relating the depth of the recess in the vane to the orifice diameter, it is possible to have a substantially uniform distribution of particles in the full cone spray.
The novel combination of the nozzle and recessed center vane produces a swirling motion or controlled turbulence of fluid as it flows through the vane and nozzle body and before entering the discharge orifice. When the liquid is discharged through the orifice as a spray, the spray forms a solid cone having a very uniform distribution throughout the transverse cross-sectional area of the cone. When the pipe diameter is changed, the vane diameter is proportionally changed and the above geometrical relationships for the channel or slot openings through the vane are maintained and the same desired uniform solid spray cone will still be produced. Similarly, when input fluid pressure or fluid flow rate is changed for the same or for different pipe diameters, the novel solid cone configuration of uniform distribution is maintained. By a controlled relation between the vane recess depth and the orifice opening, a very uniform distribution of solid spray can be obtained.
The novel vane structure of the invention can be made from any desired material including metals and plastics. A typical metal is steel and a typical plastic is polyvinyl chloride. The conduit to which the nozzle is connected can be of any desired material and may be of metal such as steel or plastic such as polyvinyl chloride.
It is an object of the present invention to provide a full cone spray nozzle which maintains a desired capacity and ensures the uniform distribution of the liquid within the full cone spray.
Another object is to ensure equal distribution of liquid in a full cone by having a novel recessed center vane.